As semiconductor memory devices capable of storing mass data for use, variable resistance memories (ReRAM: Resistive RAM) and so forth, which can be easily formed in three dimensions, have received attention. These variable resistance memories are characterized in the asymmetry of the voltage-current characteristic that greatly changes in accordance with the direction of the voltage applied to a memory cell.
These memory cells include one that exhibits asymmetrical voltage-current characteristics depending on the history of applied voltages on the memory cell.
The operation of making access to the conventional memory cells, however, cannot be applied as it is to a semiconductor memory device that uses memory cells having such the characteristics that depend on the history of applied voltages.